JAMB Chemistry questions

443 questions with answers and explanations. Tap an option to check yourself.

1. Question 21· Acids, bases and salts· JAMB

   Phenolphthalein in an alkaline solution is

   • Ayellow
   • Bcolourless
   • Cpink
   • Dred-orange

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2. Question 22· Acids, bases and salts· JAMB

   According to Arrhenius, an acid is a substance that in water produces

   • Ahydroxide ions
   • Bhydrogen ions (H⁺)
   • Coxide ions
   • Dchloride ions only

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3. Question 23· Acids, bases and salts· JAMB

   25 cm³ of 0.1 mol/dm³ NaOH neutralises 20 cm³ of HCl. The concentration of the acid is:

   • A0.125 mol/dm³
   • B0.08 mol/dm³
   • C0.2 mol/dm³
   • D0.05 mol/dm³

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4. Question 24· Acids, bases and salts· JAMB

   What volume of 0.2 mol/dm³ NaOH neutralises 20 cm³ of 0.1 mol/dm³ H₂SO₄?

   • A20 cm³
   • B10 cm³
   • C40 cm³
   • D5 cm³

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5. Question 25· Acids, bases and salts· JAMB

   A strong acid is one that

   • Ais very concentrated
   • Bis completely ionised in water
   • Chas a pH of 7
   • Ddoes not conduct electricity

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6. Question 26· Acids, bases and salts· JAMB

   According to Arrhenius, a base is a substance that in water produces

   • Achloride ions
   • Bhydrogen ions
   • Chydroxide ions
   • Doxide ions

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7. Question 27· Acids, bases and salts· JAMB

   20 cm³ of 0.15 mol/dm³ H₂SO₄ exactly neutralises 30 cm³ of NaOH solution. Find the concentration of the NaOH.

   • A0.1 mol/dm³
   • B0.2 mol/dm³
   • C0.3 mol/dm³
   • D0.15 mol/dm³

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8. Question 28· Acids, bases and salts· JAMB

   How many moles of sodium hydroxide are needed to neutralise 20 cm³ of 0.1 mol/dm³ tetraoxosulphate(VI) acid?

   • A0.02 mol
   • B0.002 mol
   • C0.004 mol
   • D0.001 mol

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9. Question 29· Acids, bases and salts· JAMB

   An acid reacts with a trioxocarbonate(IV) to produce

   • Aan alkali only
   • Ba salt and hydrogen
   • Ca base and water
   • Da salt, water and carbon(IV) oxide

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10. Question 30· Acids, bases and salts· JAMB

    Find the pH of a 0.01 mol/dm³ solution of hydrochloric acid, assuming complete ionisation.

    • A1
    • B2
    • C0.01
    • D12

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11. Question 31· Acids, bases and salts· JAMB

    Which of these is an amphoteric oxide?

    • Acalcium oxide
    • Bsodium oxide
    • Csulphur(VI) oxide
    • Daluminium oxide

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12. Question 32· Acids, bases and salts· JAMB

    The salt formed when zinc reacts with dilute tetraoxosulphate(VI) acid is

    • Azinc oxide
    • Bzinc chloride
    • Czinc trioxonitrate(V)
    • Dzinc tetraoxosulphate(VI)

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13. Question 33· Air· JAMB

    Air is regarded as a mixture because

    • Aits components can be separated by physical means
    • Bit contains oxygen
    • Cit is colourless
    • Dit supports burning

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14. Question 34· Air· JAMB

    The percentage of argon in dry air is about

    • A78%
    • B21%
    • C0.9%
    • D0.03%

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15. Question 35· Air· JAMB

    Which gas in the air do green plants use for photosynthesis?

    • Aargon
    • Bnitrogen
    • Ccarbon(IV) oxide
    • Dneon

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16. Question 36· Air· JAMB

    A candle burning in a closed jar soon goes out because

    • Athe oxygen in the jar is used up
    • Bthe jar becomes too hot
    • Cnitrogen is produced
    • Dthe wax runs out

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17. Question 37· Air· JAMB

    The approximate percentage by volume of carbon(IV) oxide in clean air is

    • A1%
    • B21%
    • C0.04%
    • D78%

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18. Question 38· Air· JAMB

    Oxygen and nitrogen are obtained industrially from air by

    • Afractional distillation of liquid air
    • Belectrolysis of water
    • Cheating limestone
    • Dburning charcoal

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19. Question 39· Air· JAMB

    Which gas turns lime water milky but has NO effect on acidified potassium heptaoxodichromate(VI)?

    • Aammonia
    • Bsulphur(IV) oxide
    • Ccarbon(IV) oxide
    • Dhydrogen sulphide

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20. Question 40· Air· JAMB

    Incomplete combustion of fuels in a limited supply of air produces

    • Aoxygen
    • Bcarbon(II) oxide
    • Cnitrogen
    • Dozone

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